Synthetic detergent compositions



able for the preparation of the detergent com -estate.

United States {Email SYNTHETIC DETERGENT CQMPGSITIONS Richard D.Stayner, Berkeley, Calif, assignor to Cali fornia Research Corporation,San Francisco, Calif, a corporation of Deiawnre No Drawing. ApplicationMarch 2, was Serial No. 413,713

Claims. (Cl. 252-152) This invention relates to anionic syntheticdetergent compositions capable of producing good quality, stable, andpersistent foam upon being dissolved in water in concentrationsconventionally employed in household washing and in commercial laundrypractice.

Aqueous wash solutions of a number of known anionic detergents whenemployed in non-automatic and auto matic agitator-type washing machines,although efficient insofar as their detersive or cleansing action isconcerned, produce but very little foam in the presence of soil, and

this foam ordinarily has a lacy, unstable texture, and

readily collapses and disappears during the agitation of the contents ofthe tub of a washing machine.

it is generally extremely difiicult, if not impossible, to predict thefoam characteristics of an anionic detergent containing in addition to asulfate or a sulfonate group an intermediate linkage, e. g., an ester,an ether, or an amide linkage. Nor can one foretell with a sufficientdegree of certitude whether or not the addition of a compound found tobe capable of improving the foam performance of a certain particulartype or group of anionic organic sulfate or sulfonate detergents willsimilarly influence the foam behavior of another type or group ofanionic sulfate or sulfonate detergents containing an additional or adifferent intermediate linkage. It is, therefore, evident thatformulation of synthetic anionic detergent compositions possessing ahigh degree of Washing efficiency and at the same time capable ofsatisfactory foam performance substantially equivalent to that of thebetter household laundry soaps presents a difficult problem to thoseengaged in the detergent art.

Water-soluble alkylolamide sulfates of straight-chain saturated C to Cfatty acidsin which the hydrophobic organic group is linked to thehydrophilic sulfate group through an amido linkage have been known inthe art as effective anionic detergents; however, their foam performanceis not as satisfactory as that of the conventional laundry soaps, andwhile they produce an adequate volume of a fair quality foam, thepersistence of this foam under conditions of agitation is low.Consequently, the art has been seeking a long time for the ways toimprove their foam characteristics so as to make the detergentcompositions containing these organic sulfates acceptable to consumers.

I. have found that synthetic detergent compositions containing as theiractive organic detergent component a member of a certain hereinafterdefined group of water-soluble sulfated alkylolamides of straight-chainsaturated C to C fatty acids, such as are commonly derived from coconutoil and containing, in addition, a straight-chain saturated C 0 to Caliphatic alcohol as a foam improving agent, upon dissolution in waterin dilute concentrations from.0.l to 0,4 commonly employed in thelaundering practice, will produce c pious, stable andpersistent foamwhenemployed to wash soiled clothes in the tub of awashingmachine.

The structure of fattyiacidialkylolamide sulfates suit;

2,843,550 Patented July 15, 1958 ice of my invention can be representedby the following formula:

in which R is a straight alkyl chain having 7 to 17 carbon atoms; R is ahydrogen, or a C to C alkyl group; R" is a hydrogen or a methyl groupand preferably a hydrogen; M is an alkali metal and preferably sodium;and x is an integer from 1 to 3 and preferably from 1 to 2. In addition,R may also be the grouping: -i-i (i3iii{}JIFSG M shown in the aboveformula. These organic sulfates and their preparation have beendescribed in the art, for instance, in German Patent No. 633,334.

The straight-chain saturated C to C aliphatic alcohols, added to thedetergent compositions to improve their foam performance, are present inamounts which may range from about 5 to about based on the weight of theactive alkylolamide sulfate, and those containing from 12 to 16 carbonatoms in their molecule (lauryl, myristyl, and cetyl) are particularlyeffective in enhancing foam performance of detergent compositionscontaining fatty acid alkylolamide sulfates as their organic activecomponent.

The organic alkylolamide sulfate detergents have been produced in thepast from coconut oil fatty acids containing from 8 to 18 carbon atomsin the molecule. However, in view of the fluctuating market and thefrequently recurring scarcity of coconut oil, the employment of coconutoil fatty acids tends to increase the cost of production of detergentcompositions containing a kylolamide sulfates as their organic activecomponent. The saturated C to C fatty acids such as are obtainable byknown hydrogenation procedures from tallow and usually containing from60 to 70% by weight of stearic acid heretofore have been consideredunsuitable for the formulation of detergent compositions capable ofproducing satisfactory stable foams. Dilute aqueous solutions (0.1 to0.4% concentration) of the detergent compositions containing sulfatedalkylolamides of hydrogenated tallow fatty acids produce but a littlevolume of an unstable, lacy foam, and the addition of straight-chainsaturated C 0 to C aliphatic alcohols in the: same manner as describedhereinabove with reference to sulfated alkylolamides of coconut oilfatty acids is ineffective in producing adequate foam volume.

Addition of C to C alkylolamides of saturated fatty acids such as lauricethanolamide or lauric isopropanolamide reported in the art as additivesfor the improvement of foam properties of certain classes of syntheticanionic detergents is found inadequate to bolster and to stabilize thefoam of sulfated alkylolamides of hydrogenated tallow fatty acids. Itis-true that improved foam persistence, i. e., continuous presence offoam in the tub of a washing machine during the agitation cycle of atleast 20 minutes, may be achieved by such an addition, but the staticstability and the quality of the foam are inordinately poor. The foam isextremely unstable and lacy in its texture, and readily collapses in thepresence of soil in the course of agitation.

I have found that by employing sulfated alkylolamides of hydrogenatedtallow fatty acids as the essential organic detergent ingredient of theformulations of my invention and by replacing a portion of thesesulfated alkylolamides not exceeding 8 5% by weight of the well-known Cto C monoalkyl benzenesulfonates, an ample volume of foam of asatisfactory static stability and quality will be and p'rererably the Cte C straight chain saturated aliphatic alcohols present in theseformulations in accordance with my invention will secure an adequatedegree of persistence and stability of this foam during the agitation ofthe wash solution containing soiled articles or fabrics in the tub of awashing machine.

Sulfated alkylolamides of hydrogenated tallow fatty acids employed informulating the detergent compositions of my invention are prepared byreacting suitable pri mary or secondary straight-chain C to O,alkylolamines, and preferably C to C alkylolamines, with saturated C toC fatty acids produced from hydrogenated tallow, sulfating the resultingalkylolamides and neutralizing the sulfation product with a suitablebase, aqueous sodium hydroxide or sodium carbonate being preferablyemployed for this neutralization.

In view of the comparatively low cost of C to C monoalkyl benzenesulfonates, they may be employed in the detergent formulations of myinvention to replace the sulfated alkylolamides of C to C fatty acids,irrespective of the original source of these acids: coconut oil, tallow,cottonseed oil, and the like, and in amounts up to 85% by weight of thetotal organic detergent component. When the sulfated alkylolamides arederived from hydrogenated tallow, addition of these monoallryl benzenesulfonates, and particularly in amounts from about 50 to about 85% byweight of the total organic detergent component, is particularlyeffective in securing the desirable volume of foam. These formulationscontain, furthermore, from 5 to 70% of a C to C normal saturatedaliphatic alcohol, based on the weight of the sulfated alkylolamides, asan agent for the enhancement of foam persistence. If monoalkyl benzenesulfonates are present in the detergent composition, the weight ratio ofthese sulfonates to the sulfated alkylolamides of fatty acids may be ashigh as 3:1 or even higher, ratios of lzl and 2:1 furnishing the bestresults as regards foam properties (performance) and washing efliciency(detergency). The preparation of C to C monoalkyl benzene sulfonates iswell known to those skilled in the art and is described, for instance,in U. S. Patent No. 2,477,383, issued to A. H. Lewis, and U. S. PatentNo. 2,218,472, issued to Kyrides. As pointed out hereinbefore, thepresence of these C to C alkyl benzene sulfonates in a compositioncontaining active sulfated alkylolamides of fallow fatty acids, as wellas in compositions containing active sulfated alkylolamides ofhydrogenated cottonseed oil fatty acids, soybean oil fatty acids, andthe like, insures an adequate foam stability and a satisfactory foamquality, whereas in those compositions containing sulfated alkylolamidesof coconut oil fatty acids, their em ployment effects a substantialreduction of costs.

The excellent foam properties of the detergent compositions of myinvention are not affected by the presence of detergent builderscommonly employed in anionic detergents, and, in particular, inheavy-duty detergents such as are usually employed in the launderingpractice. Detergent builders are water-soluble inorganic salts such asneutral salts of strong acids (chlorides or sulfate component (whichmay, if desired, contain a detergent monoallryl benzene sulfonate) andto the C 5 to normal saturated aliphatic alcohol as the foam-improving 4agent, may contain in each 100 parts by Weight, based on the content ofsolids in a particular composition, from 60 to 90 parts by weight ofwater-soluble inorganic salt builders, the sodium salt builders beingusually preferred. These sodium salts include sodium carbonate, sodiumtripolyp'nosphate, tetrasodiurn pyrophosphate, sodium sulfate, bi; x,sodium chloride, sodium silicates, etc.

Well-known alkylolamide foam improvers such as lauric isopropanolamideand lauric ethanolamide may be added if so desired to my detergentformulations to enhance the tolerance of soil by the foam. Theseadditions in no way diminish the beneficial effect of the presence of anormal C to C saturated aliphatic alcohol agent on foam persistencewhile washing soiled laundry or dishes under conditions of agitation.

if desired, other conventionally employed additives such as anti-caltingagents, optical bleaches, perfume, and coloring agents may be present inthe detergent compositions of my invention. Sodium carboxymethylcellulose or sodium salts of celluronic acids may also be present insmall amounts as extenders, as well as for the purpose of preventingre-deposition of the soil. N alkyl glycines and diglycines which act asskin emollients and prevent skin rashes and erythemas may be likewiseadded. These additives are usually present in amounts less than 5% byweight, based on the total content of solids in the detergentcomposition, and in all events are employed in such amounts as not tointerfere with the improvement of the foam properties describedhereinbefore.

Generally, the blending of the various ingredients of my improveddetergent compositions is carried out by mixing the ingredients to forma solution or slurry, and then drying the resulting mixture to the solidparticle form, or evaporating it to form a paste, or, yet, diluting itto produce a liquid concentrate. When a detergent composition is tocontain the combination of fatty acid alkylolamide sulfates and alkylbenzene sulfonates as its active ingredient, it is preferred tosulfonate the alkyl benzene stock first (for details of sulfonation, seebulletin of Oronite Chemical Company of San Francisco, California,published in 1950 and entitled, Alkane-Product and ProcessingInformation), and then to add the fatty acid alkylolamides to thesulfonation reaction mixture. The alkylolamides are sulfated by theunreacted sulfuric acid in the sulfonation reaction mixture. Thequantityof the sulfonating agent required for the preparation of a particularmixture of alkyl benzene sulfonic and acid sulfates of alkylolamides offatty acids is governed by the desired weight ratio of detergent organicsulfates to alkyl benzene sulfonates in the final neutralized product.If desired, the sulfonating agent, e. g., fuming sulfuric acid, may beemployed in such an amount that the unreacted sulfuric acid in thesulfonation product mixture would be insufficient to sulfate all of thealkylolamides, and a portion thereof thus may be permitted to remain inthe liquid mixture of sulfated alkylolamides and alkyl benzene sulfonicacid, and would tend to improve the soil tolerance of the foam formed byaqueous wash solutions of the final detergent formulations. Theresulting mixture of acids is then neutralized. Thereupon theneutralized slurry or solution receives the addition of the normalsaturated C to C aliphatic alcohol and also detergent builders and suchother additives as may be required, and finally is converted to thedesired form: solid particles, or a paste, or a liquid concentrate. Byfirst sulfonating the alkyl benzene stock in a known manner, and thensulfating the alkylolamides in the sulfonation reaction mixture, asuperior product is obtained with all ingredients being uniformlydistributed throughout the final product whether offered in the form ofsolid particles, a semi-solid paste, or a liquid concentrate.

Several series of foam evaluation tests have been carried out. Theseseries comprised-numerous benchf tests in the laboratory using diluteaqueous wash solutions of the detergent compositions prepared inaccordance with my invention. The active organic portion of each 100parts of the solid dry particulate formulations employed for these testswas equal to from 20 to 22 parts by weight and consisted of sodium saltsof sulfated alkylolamides of C to C fatty acids, sodium 0,; to Cmonoalkyl benzene sulfonates, and a straight-chain C to C saturatedaliphatic alcohol, e. g., normal decanol, dodecanol, tetradecanol,hexadecanol, and octadecanol. In addition, the same solutions weretested in an agitator-type non-automatic washing machine under theconditions closely approximating those occurring in the conventionaloperation of a domestic washing machine. Data from severalrepresentative tests of a series designated as Series A are offered inthe following Table I in order to illustrate the advantages of theimproved detergent composition of the present invention. Sodium C to Cpolypropylene benzene sulfonate was employed as a representative (3,, toC monoalkyl benzene sulfonate in the tests of this series. The sulfatedalkylolamides employed were those amides of fatty acids derived fromhydrogenated tallow, and the alcohols selected as representativealcohols effective in securing better foam persistence were dodecanoland hexadecanol. Detergent builders were present in the followingamounts: 30 parts by Weight of sodium tripolyphosphate; parts by weightof tetrasodium pyrophosphate; 5 parts by weight of sodium silicate; theremainder to make 100 parts by weight being sodium sulfate. The ratio ofNa O to SiO in the sodium silicate was 1:3.2. Solid, dried particles ofthe detergent formulation were dissolved in soft water from thelaboratory tap (50 p. p. m. of Ca-Mg hardness) at 120 F. to make up 500ml. of a 0.15% solution in 2-liter beakers. The solutions were thentested at the bench by agitating the contents of the beakers with theaid of propeller-type stirrers for one minute. The contents were thenallowed to stand for one minute and foam heights in millimeters weredetermined. In another 15 minutes after the termination of theagitation, the foam heights were measured again. Stability of the foamwas rated by observing the rate of oil ate between Poor and Good wasrated as Fair. The size of the foam bubbles and the body or feel thereofwere also observed. Foam of a Good quality is made up of uniformlysmall-sized, dense-bodied bubbles and has high bulk viscosity. It iswhite and opaque. Foam of a Poor quality has large-sized bubbles, a lowbulk viscosity and tends to be lacy. It is, furthermore, greyish incolor and transparent. Foams, the stability of which lies between Poorand Good, were rated as Fair.

In the parallel washing machine tests of the same series, carried outfor the purpose of determining foam persistence, the bowl or tub of themachine was filled with the wash solution and charged with a load ofsoiled cotton towels. In each test run the contents were agitated underidentical conditions and at the same temg'terol'lii'fi (l2tl-l25 F).Solutions were prepared using hem soft water (50 p. p. m. of Ca-Mghardness) and hard water (300 p. m. m. of Ca-Mg hardness). Foam wasobserved at regular intervals, and its persistence was rated. When thesuds disappeared from the surface of the wash solution in the tub inless than 5 minutes after the beginning of agitation, the persistencewas given a rating of 1. When from 5 to 10 minutes was required for thedisappearance of the foam, the persistence was rated as 2. When from 10to 20 minutes was required for the disappearance of the foam, itspersistence was assigned a rating of 3. The foam which lasted for 20minutes under the conditions of operation, but was less than /2 inchhigh above the surface of the liquid in the tub, was given a persistencerating of 4. When, after 20 minutes of operation, the height of the foamwas from /2 to 1% inches above the surface of the liquid, thepersistence was assigned a rating of 5. When, after 20 minutes, the foamretained a height from 1% to 3 inches above the surface of the liquid,the persistence was rated as 6. Finally, when the foam after 20 minutesstayed at a level higher than 3 inches above the surface of the liquid,the persistence was asfoam decay under mechanical stress as by blowingon a signed a maximum rating of 7.

TABLE I Foam evaluatzon data Foam Performance Bench Tests WashingMachine Foam-Improv- Monoalkyl Te t Test Sulfated Allcylolamide ofHydro- Parts ing Straight- Parts Benzene Run genated Tallow Fatty Acidsby chain Saturated by Sulfonate No. Wt. Aliphatic Wt. in Parts FoamHeight Alcohol by Wt. in mm. In Soft In Hard Foam Foam Water, Water,

Stability Quality p. p. m. 300 After After p. p. m 1 min. 15 min.

1 Ethanolamidc 10 Dodecanol. 2 10 82 68 2 do. 5 do 2 15 83 67 3 10Hexadecanoh. 2 10 82 67 4 3 d 2 17 8O 68 5- 10 10 82 48 6- 5 15 86 57 717 82 68 8- 15 83 9- 73 30 10 18 Hcxadecanol 2 60 55 11..- I i. one 2087 68 12..- n-Propanolamide. 10 Dodocanol. 2 10 80 68 13..- do 10Hexadecanol. 2 10 82 14 d0 10 None 10 80 50 15 Diethanolamide.. 5 do .115 74 57 16 do 5 Hexadecanol. 2 15 48 40 17. do. 5 Dodecano1 2 15 75 4018. do 10 do 2 10 65 48 19 Diethanolamide and monoetha- 10 v d0 2 10 89Good nolamide (weight ratio 1:1). 20 Ethanolamide 8 .do 2 12 do.

small volume of foam gently with air: an unstable foam rapidly collapseswhen blown upon. High degree of stability, when foam withstands beingblown upon, was rated at Good; stability of weak, almost immediatelycollapsing foam was designated as Poor; stability intermedi- The resultsoffered in the table strikingly illustrate the advantages of employingdetergent formulations of my invention whenever formation of a dense,stable, and persistent foam is desirable in the laundering operations.Thus, the team of the formulation; which contained sulfated alkyloamidesof hydrogenated tallow fatty acids as the sole active organic detergentcomponent, in the absence of added normal saturated C to C aliphaticalcohol, produces but a very low volume of foam of Poor quality and Poorstatic stability (test run #9), an improvement, however, being notedupon addition of a normal C to C saturated aliphatic alcohol (test run#10). When alkyl benzene sulfonate was the only organic detergent and inthe absence of a normal saturated C to C aliphatic alcohol, the foamstability and foam quality were very poor (test run #11). When thecombination of a sulfated alkylolamide detergent derived from tallowfatty acids with an alkyl benzene sulfonate detergent was employed inthe absence of a normal C to C saturated aliphatic alcohol (e. g., testruns and #6), the foam still lacked good quality and static stability.Surprisingly, however, when similar combinations received an addition ofa normal C to C saturated aliphatic alcohol (test runs Nos. 1, 2, 3, 4,8, 12 and 13), an adequate volume of Good quality, stable foam wasproduced and the foam persisted under the conditions of agitation.

The foam produced by the formulations, the active organic portion ofwhich contains at least 15% by Weight of sulfated alkylolamides orhydrogenated tallow fatty acids in combination with up to 85% of C to Cmonoalkyl benzene sulfonates, and furthermore containing from 5 to 70%by weight, based on the sulfated alkylolamide ingredient, of a normalsaturated C to C aliphatic alcohol, is similar in appearance and feel tothe suds of conventional good-quality household soap.

Good detergency was obtained by using aqueous wash solutions (0.1 to0.4% concentration) prepared with these formulations, as determined bythe Launderometer Method, particularly when washing soiled cotton goods.

in similar series of test runs (B) and (C) employing detergentformulations containing: (Series B), sulfated alkylolamides of coconutfatty acids as the only organic detergent component and from 5 to 70% byweight thereof of a normal saturated C to C aliphatic alcohol; and(Series C), a combined organic detergent component,

at least 15% by weight thereof being sulfated alkylolamides of coconutoil fatty acids and the remainder being C to C alkyl benzene sulfonates,together with from 5 to 70% by weight of a normal saturated C to Caliphatic alcohol, based on the content of sulfated alkylolamidedetergent. In each of these Series (B) and (C), good foam performanceand detergency have also been observed. Dilute aqueous solutions of theformulations containing in the organic detergent portion at least 15% byweight of sulfated alkylolamides of hydrogenated tallow fatty acids andup to 85% by weight thereof of alkyl benzene sulfonates, and furthercontaining from 5 to 70% by weight, based on the alkylolamide sulfate,of a normal saturated C to C aliphatic alcohol (Series A) are found tobe slightly more effective in detergent action, particularly at lowuse-concentrations in hard water, than similarfdilute solutions offormulations containing sulfated alkylolamides of coconut oil fatty acidas the only detergent (Series B), or containing blends thereof with C toC alkyl benzene sulfonates (Series C).

It is known that detergent compositions containing C to C monoalkylbenzene sulfonates as the sole active organi e component suffer from thedrawback of unsatisfactory foam stability. Hence, it is entirelyunexpected that the detergent compositions, in which the active organiccomponent is a combination of these sulfonates with sulfatedalkylolamides of C to C saturated fatty acids, derived from coconut oilor from taliow or from other suitable organic materials, and whichcontain C to C normal aliphatic alcohols in accordance with theinvention, upon being dissolved in water to form dilute aqueous washsolutions, produce foams of excellent quality, similar in texture to thesoapsuds, and capable of lasting (persisting) throughout the duration ofa complete washing cycle in the bowl of an agitator-type Washingmachine.

I claim:

1. A detergent composition consisting essentially of alkali metal saltsof sulfated C 43 alkylolarnides of C C hydrogenated tallow fatty acids,alkali metal Cry-C15 monoalkyl benzene sulfonate detergent, the formerbeing present in an amount, by weight, of about 15% to 50%, and thelatter, 50% to 85%, by weight, of the total of the two, and as afoam-improving agent, about 5% to 70%, by weight, based on the sulfatedalkylolamide salt, of a normal, saturated C -C aliphatic alcohol.

2. A detergent composition consisting essentially of alkali metal saltsof sulfated hydrogenated tallow fatty acid ethanolamide, alkali metal CC monoalkyl benzene sulfonate detergent, the former being present in anamount, by weight, of about 15% to- 50%, and the latter, 50% to 85%, byWeight, of the total of the two, and as a foam-improving agent, about 5%to 70%, by weight, based on the sulfated alkylolamide salt, of a normal,saturated C -C aliphatic alcohol.

3. A "built detergent composition consisting essentialiy of about 10 toby weight, of the detergent com position of claim 1 and about 60 to 90%,by weight, of water-soluble inorganic salt builders.

4. The composition of claim 1 wherein the alkali metal of the sulfatedalkylolamides and of the C -C monoalkyl benzene sulfonate detergent issodium.

5. The composition of claim 4 wherein the C -C monoalkyl benzenesulfonate detergent is a (I -C monoalkyl benzene sulfonate detergent.

References Cited in the tile of this patent UNITED STATES PATENTS OTHERREFERENCES Perry and Schwartz: Surface Active Agents, 1949,

, pages 117, 118.

1. A DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF ALKALI METAL SALTSOF SULFATED C2-C3 ALKYLOLAMIDES OF C14C18 HYDROGENATED TALLOW FATTYACIDS, ALKALI METAL C9-C18 MONOALKYL BENZENE SULFONATE DETERGENT, THEFORMER BEING PRESENT IN AN AMOUNT, BY WEIGHT, OF ABOUT 15% TO 50% ANDTHE LATTER, 50% TO 85%, BY WEIGHT, OF THE TOTAL OF THE TWO, AND AS AFOAM-IMPROVING AGENT, ABOUT 5% TO 70%, BY WEIGHT, BASED ON THE SULFATEDALKYLOLAMIDE SALT, OF A NORMAL, SATURATED C10-C18 ALIPHATIC ALCOHOL.